Method of regulating the discharge of molten metal from ladles



UHU HNLI -LHKDH UUR www Aug 17, 1955 J. B. wAGsTAFF 3,200,457

METHOD OF REGULATING THE DISCHARGE OF MOLTEN METAL FROM LADLES f .II Ill Filed March 9, 1964 INVENTOR A/R FLOW, cc/sec FLE? 1 JAMES E. WAGSTAFF Mm A l orney United States Patent O 3,200,457 METHOD F REGULATING THE DISCHARGE OF MOLTEN METAL FROM LADLES James B. Wagstalf, Franklin Township, Westmoreland County, Pa., assignor to United States Steel Corporation, a corporation of New Jersey Filed Mar. 9, 1964, Ser. No. 350,231 7 Claims. (Cl. 22-209) This invention relates to the casting of molten metal and, as indicated, to a method of regulating the rate at which molten metal is discharged from refractory-lined ladles. Such method, more specifically, operates to slow the rate at which the metal teems through a nozzle in the bottom of the ladle, this being accomplished in a manner to be described by introducing gas in regulated quantities into the nozzle orifice to restrict the gravitational liow of metal therethrough.

The teeming operation of ladles used in casting hot metal is controlled by stopper rods that are moved vertically between open and closed positions with respect to the ladle teeming nozzles. After a stopper rod is raised to open position, there is nothing to restrict the discharge of metal through the teeming nozzle, which continues until the ladle is empty or the stopper rod is lowered to its closed position. The unrestricted discharge of molten metal in this manner is undesirable especially in continuous casting operations under conditions that may result in the molten metal being fed to the casting apparatus at too rapid a rate.

An object of this invention, accordingly, is to regulate the rate at which molten metal is discharged from a ladle teeming nozzle. A further and related object is to feed gas in regulated quantities into the orifice of a ladle nozzle while metal is teeming therethrough to retard the rate at which the metal is discharged from the ladle.

Other objects and advantages of the invention will become apparent from the following description and the accompanying drawings, in which:

FIGURE l is a fragmentary sectional view of a teeming ladle equipped with a nozzle and stopper rod that are constructed for the practice of the method of this invention, the stopper rod being shown in its lowermost or closed position;

FIGURE 2 is an enlarged View of a portion of the ladle structure shown in FIGURE l, but showing the stopper rod in its raised or open position; and

FIGURE 3 is a graph illustrating the manner in which the method of this invention operates to regulate the flow of liquid through a discharge orifice.

The ladle structure shown in FIGURE l of the drawings is similar to that shown in U.S. Patent No. 2,005,311 issued June 18, 1935, to H. R. Belding. As disclosed in this patent, a ladle A for holding molten iron or steel comprises a shell 1 of boiler plate and a lining 2 of fire brick, or other refractory material. A vertically extending teeming orifice 3 is provided in the bottom of ladle A by a nozzle 4 of fire clay or other suitable refractory material, which is normally closed by a stopper-head S of fire clay or graphite, the latter being suitably aflixed to a stopper rod assembly, generally indicated at B. The

stopper rod assembly B extends upwardly t-o the top of "ice head 5 mentioned above has an axially extending opening 10 that is defined in part by a metal sleeve 11 which forms part of a connection for securing the stopper-head to the tube 7. The opening 10 is an extension of the passage through the tube 7 and is axially alined with the nozzle orifice 3 so that gas delivered through a supply conduit 12 connected with the upper end of the tube 7 will be discharged through the nozzle 4 when the stopper rod B is in the closed position shown in FIGURE 1. The ladle structure thus far described is essentially similar to that shown in the above-mentioned Belding patent.

A throttle valve 13 is provided in the supply line 12 for regulating the supply of gas flowing through the stopper rod tube 7 to the nozzle orifice 3. The valve preferably is manually adjustable although it may be operated automatically from a remote location if desired. The Valve 13 further connects the tube 7 to a pressurized source of gas which, for the purposes of this invention, is preferably an inert gas, such as argon, although air, oxygen or other gas may be used. In the closed position of the stopper rod B shown in FIGURE l, which is the position it occupies when the ladle is being filled with metal and during its transfer to a teeming location, the valve 13 may be fully opened to deliver gas or air through the tube 7 and opening 10 in sufficient volume to effect cooling of the rod B according to the disclosure of the above-mentioned Belding patent.

After the ladle A has been filled and transferred to a teeming location, the valve 13, if it has been in fully-open position to effect cooling of the stopper rod, is closed to interrupt the fiow of gas before the assembly B is elevated to the open position shown in FIGURE 2 for the discharge of metal through the teeming orifice 3. With the assembly B in open position, regulation of the rate of discharge of metal through the orifice 3 in accordance with the principles of this invention, is effected by opening the valve 13 to deliver gas through the tube 7 of the stopper rod assembly B. The gas flowing through the tube 7 is discharged from the lower end of the assembly B at a point vertically above the upper end of the orifice 3. The gas leaving the lower end of the rod assembly B in the mannner is carried through the nozzle orifice 3 with the metal flowing therethrough, and operates to limit the quantity of metal that will teem through the nozzle 4 in a given period of time. Generally stated, the rate of discharge of metal through the nozzle 4 is reduced as the valve 13 is opened to deliver more gas through the stopper rod assembly B. While the maximum amount of gas that can be delivered to the rod B for reducing the discharge of metal through the nozzle 4 has not been determined, it is far less than is required for cooling the rod assembly B in accordance with the invention of the Belding patent.

The manner in which the rate of gas flow operates to vary the rate of liquid flowing through a nozzle is illustrated by the graph shown in FIGURE 3. The data for this graph was obtained by constructing a plexiglass model ladle with a bottom nozzle and a hollow stopper rod which was arranged vertically above the nozzle orifice substantially as shown in FIGURES 1 and 2. Water was maintained at a constant level in the ladle and air was passed downwardly through the stopper rod after it was elevated to open position. The rate of air flow through the stopper rod was gradually increased to determine its effect in liquid discharge and develop the information from which the curve of FIGURE 3 was plotted. As shown by FIGURE 3, the water flow or rate of discharge decreased as the air flow increased. In addition to reducing the rate of discharge, the addition of air to the liquid in this manner was found to reduce the splash that takes place when the stream of liquid moving downwardly from the nozzle stopped by a fiat surface.

While one embodiment of my invention has been shown and described it will be apparent that other adaptations and moditications may be made without departing from the scope of the following claims.

I claim:

1. A method of regulating the discharge of molten metal iiowing through a vertically extending orifice in a teeming nozzle in the bottom of a refractory-lined ladle which comprises forcing gas through said nozzle orifice to reduce the rate at which metal is discharged from said ladle.

2. A method as dened in claim 1 characterized by said gas being forced into said nozzle orifice in an axial direction from a point vertically above its upper end.

3. The method defined in claim 2 characterized further by said gas being fed to said nozzle orifice through an axial passage in the stopper rod for said ladle.

4. A method as defined in claim 3 characterized by varying the rate at which gas is delivered to said stopper rod passage to vary the rate at which metal is discharged from said nozzle orifice.

5. A method of regulating the discharge of molten metal from a refractory-lined ladle which comprises forcing gas through a teeming nozzle in the bottom of said ladle while metal is flowing therethrough to thereby re- 7. A method of regulating the discharge of liquid through an orifice in the bottom of a container which comprises moving gas through said orifice while liquid is being discharged therethrough to thereby reduce the rate at which the liquid is discharged from said container.

References Cited by the Examiner UNITED STATES PATENTS 161,644 4/75 Swank 22-85 2,259,215 10/ 41 Scheurer 239-416 2,889,856 6/59 Magnuson 137-815 2,964,302 12/ 60 Tombu 239-407 3,083,422 4/ 63 Finkl 22-85 WILLIAM I. STEPHENSON, Primary Examiner.

MARCUS U. LYONS, Examiner. 

1. A METHOD OF REGULATING THE DISCHARGE OF MOLTEN METAL FLOWING THROUGH A VERTICALLY EXTENDING ORIFICE IN A TEEMING NOZZLE IN THE BOTTOM OF A REFRACTORY-LINED LADLE WHICH COMPRISES FORCING GAS THROUGH SAID NOZZLE ORIFICE TO 